[Amps] Terminology Question

[Don Havlicek]

In the early days of radio, most all circuits were BATTERY powered.
The delineation of A, B, C, etc ... referred to the batteries used to
power such devices.
The A battery was used to power the filament of the vacuum tube, and,
YES, the polarity was important in some circuits, so the terminals were
labelled:  A+ and A-
The B battery was used for plate voltage.
B+ indicating that POSITIVE voltage was connected to the plate, and B-
indicating the battery return to the 'neutral' of the circuit [usually
'ground'].
The C battery was used for grid bias, C- indicating negative bias, and
C+ indicating that the positive potential of this battery was attached
to 'neutral' [usually ground].
Hope this helps you understand.  
I'm 65, and learned all this from those who assisted me in getting my
license on my 17th birthday.  Gosh, that's a LONG time ago!
73
Don - N8DE


RMead100@aol.com wrote:
> 
> What is the origin of the B+ term in amp/radio/power supply terminology. I
> understand it to be the high voltage supply, but I do not know the origin of
> the designation and that has finally bothered me at age 52. It seems to me
> the only voltage referred to with this type of shorthand.........i.e. no A+
> or -; no B-, no C + or -.
> 
> R Meadows
> k8BUX
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